Effects of acute exercise on inspiratory muscle strength and endurance in untrained women and men.

Aim: The purpose of this study was to determine if sex differences are present in exercise-induced inspiratory muscle function in untrained humans.

Methods: Eight young untrained women (23.8 ± 1.5 y, VO2max = 33.7 ± 4.0 mL/kg/min) and men (26.1 ± 2.0 y, VO2max = 36.7 ± 1.2 mL/kg/min) performed high-intensity cycling exercise (80% WRmax) to exhaustion. Inspiratory muscle strength and endurance were assessed pre- and post-exercise by measuring maximal inspiratory pressure (PImax) and time to task failure during a constant-load breathing test (CLBT), respectively.

Results: Relative intensity and time to exhaustion during high-intensity exercise was similar between women and men. Prior to exercise, PImax was similar between sexes. After exercise, women and men showed similar reductions in PImax (W: 140.4 ± 9.9 to 124.6 ± 6.7 cm H2O, P<0.05; M: 147.7 ± 10.2 to 128.1 ± 11.1 cm H2O, P<0.05). No sex difference was found in the magnitude change in PImax following exercise (W: 15.8 ± 7.9 vs. M: 19.6 ± 4.7 cm H2O). Time to task failure on the CLBT was reduced following exercise in women (360 ± 54 to 135 ± 29 s, P<0.05) and men (270 ± 36 to 150 ± 17 s, P<0.05). Women exhibited a greater reduction in time to task failure following exercise than men (W: 225 ± 55 vs. M: 120 ± 38 s, P=0.05).

Conclusion: These data demonstrate that women exhibit a greater reduction in inspiratory muscle endurance following an acute bout of high-intensity exercise than men.